Foreign car sales in South Korea hit a new monthly high last month on the back of robust demand for foreign luxury brands, industry data showed Wednesday.

Sales of imported cars jumped 21.1 percent from a year earlier to 18,112 in July, keeping a record-breaking trend for two months in a row, according to the Korea Automobile Importers and Distributors Association (KAIDA).

The double-digit growth came amid solid demand for luxury brands made by German automakers. Foreign cars have become popular among South Korean consumers following free trade deals with Europe and the United States.

German automaker BMW ranked first in terms of best-selling brand, with 3,363 vehicles sold here in July. It was trailed by Mercedes-Benz with 3,349 units and Volkswagen with 3,157 units. Audi ranked fourth with 2,860 cars sold, and Ford came next with 917 units.

European cars were most popular, with 14,815 vehicles sold last month. The figure accounted for 81.8 percent of the total, followed by Japanese brands with a 10.9 percent share and U.S. models with 7.4 percent.

Volkswagen's Tiguan 2.0 TDI BlueMotion was the most popular model with 906 units sold, beating Audi's A6 2.0 TDI with 681 units sold. It was followed by BMW's 520d with 550 units sold.

Vehicles with an engine capacity of 2 liters or less were most popular, posting a 55 percent share. It was trailed by cars with an engine displacement of between 2-3 liters, which took up 33.9 percent.